Tempering apparatus for refrigerated air



Jan. 25, 1944. R, 1 PALMER 2,340,252

"TEMPERING APPARATUS FOR REFRIGERATED yA'IR Filed Jan.f4, 1941v INVENTOR Patented Jan. 25, 1944 ffUNITED STATES PATENT oFFicE TEMPERmG APPARATUS. FOR REFRIGER- ATED A m Robert T. Palmer, Sharon, Mass., assignor to B. F. Sturtevant Company, Boston, Mass.

Application January 4, 1941, Serial No. 373,159

9 Claims.

This invention relates to tempering apparatus for refrigerated air and relates more particularly to' Yapparatus for blending warm air with air chilled to a low dew point for increasing 4the sensible heat thereof.

vIn air cooling systems in passenger vehicles such,ior example, as railway passenger cars, it has been the practice in warm weather, to blow the air from the refrigerative dehumidifier directly into the passenger space without reheat and tov control the temperature within the passenger space by cycling the refrigerant vcompressor. This has resulted during the off cycles of the compressor in rises in relative humidity due both -to the absence of any dehumidication, and to the re-evaporation of moisture from the commonly used, direct expansion evaporator tubes, which was condensed thereon during the on cycles of the compressor. To overcome the rises in relative humidity, it has been proposed to operate the compressors continuously and to reheat the air before delivery by steam heaters controlled by dry bulb thermostat in the passenger space. The operating costs however of such an expedient are believed to be out of all proportion to be benefits gained.

In stationary air conditioning systems such as theaters the air is chilled to a low dew point temperature for effective dehumidification and the air is reheated by mixture with it of recirculated air known as by-pass air. The reissue patents, Lewis No. Re. 16,611 and Fleisher No. Re. 20,088 disclose such systems. The by-pass systems however require plenum mixing chambers, by-pass air ducts and additional fans and there is insuiiicient space for such equipment in railway passenger cars.

This invention provides a modied by-pass system for railway passenger cars by providing in one embodiment, ejectors in the lower wall of an overhead central duct, which induce the iiow of recirculated air as by-pass air, through ceiling inlet grilles on both sides of the duct, the by-pass air being mixed with the dehumidied air prior to its discharge into the passenger space, thereby raising its sensible heat.

An object of the invention is to reheat the chilled, dehumidied air in air conditioning systems for passenger vehicles, by mixture with warm air.

Another object of the invention is to cause the chilled, dehumidied air in air conditioning systems for passenger vehicles, to induce the flow into it of warm air prior to delivery into the passenger space,y for raising the sensible heat of the delivered air;v Y

' The invention will now be described with reference rto the drawing of which: y Y

t Fig. 1 is a cross-section through a railway passenger car equipped with one embodiment of this invention, taken along the lines I I of Fig'., v2-is a plan view in section looking from the passenger space of the car of Fig. 1 and-taken along-the lines 2-2 of Fig. `1;

Fi-g.- 3 is a transverse section` through a railway passenger car equipped with another embodiment ofthe invention utilizingV outdoor air as by-pass air, andk y v l Y p Fig. 4 is a transverse section similar to Fig. 1 except .that the car of Fig.` 4 is a so-called turtle backV or stream-lined car, while the 4car of Fig. 1 is Vone having a clerc-story space. y l Referring first to Figs. 1 and 2the car 6 contains in one end, a conventional refrigerative dehumidierl equipped with the blow-through fans 8 for drawing in outdoor air through the inlet 9, and recirculated air through the inlet I0, for

passing `the mixture through the dehumidier 1 andzforforcing the dehumidied air under pressure into the overhead centrally placedduct II. The duct vII lis provided, forexample, with a plurality of slitsV I2 in its lower wall I3, the slits eachibeing, for example, ve feet long and four in number and spaced apart equal distances. The ceiling I4 contains below the slits I2, the air outlet grilles. I5 through which the conditioned air is discharged into the passenger space. The recirculated airinlet grilles I6 are placed in: thefceiling I4 on opposite sides of the outlet grilles I5. f Y f yThe outer longitudinal sides of the grilles IB are connected to the adjacent lower edges of the duct Il by the airl guiding partitions I'I.. The

. vertical partitions I8 extend upwardlyfrom the .serve to guide the recirculated air smoothly into the upper end of the passage between the partitions I8. y

The transverse sides of the grilles I5 and I6 are formed by the common walls 20 which with the partitions Il, the lower wall I3 of the duct I I, the partitions I9 and the grilles form passages which are closed except for the slits I2 and the grilles I5 and I6. It is thus seen that there is provided at each slit I2 a complete air blending unit, a plurality of such units being spaced apart and associated with the duct Il for. tempering the air discharged therefrom.

In operation, the dehumidified air is passed into the duct II at a static pressure of say 0.6" of water. The air under pressure passes in high velocity jets through the ejectornozzle slits IZ` and discharges into the passage formed between the partitions I 8 and the end partitions 2U. This- `ejector action induces the flow ofthe air recir culated from the car, into the passage between the partitions I3. The recirculated air is vmixedv in this passage with the chilled dehumidifed `air and increases its sensible heat. Tests of a structure equivalent to that illustrated herein have shown that the dehumidiiied airas 40%' ofi the total air can eiiectively` induce 60% of the total air as recirculated air so'that thereiis ample' by-pass eiectf.

` vIt is not desired, ofcourse, that'theair-from the grille I5 bedischarged inafblastinto the passenger space, and it is a feature of theembodiment of this invention illustrated Vbyl-Figs. 1, 2, and 4 thatthe relative'arrangements ci4 the grilles I5 and IB preventthis.; The air' discharged from the-grilles |5'tends to flow in shortcircuit now into the vgrilles I6 as indicated bythe arrows of Fig. 1. The-side currents thus prevent a down blast into the passenger space which instead is cooled by the now of the cold air particlesby gravity into the -passenger space,vfrom the air currents directed towards the-side ofthe car. Some air is projected downwardlyinto'the passenger spa'ce'from the-grilles I5 but this air will have been tempered'by Ythe by-pass air and it enters the' center aisle for aidingin the displacement of the warm air toeach side'thereo'f for iiow into the grilles I5.

'I'hereis not much space'in-theupper part of' a'railway passenger car for ductsand air mixing passages, etc., but'the available space -is `sufficient for the installation of apparatus effectively embodying this invention. The ordinary overhead duct now used handles 100% of the air discharged into the passenger space. Since the overhead duct according to this invention handles only 40% of the total air, its size may be correspondingly reduced. Furthermore it is desirable to have'higher static air pressures in the duct than have been provided in the past, for ejector action so that the size of the duct may be reduced more than 60% through the movement of the air therethrough'at higher pressures.`

Fig. 3 illustrates an embodiment of the invention in which outdoorair is blended by ejector actionwith the dehumidiiied air. The ventilator 22 admits outdoor air into the clerc-story space 23. The air outlet grille I5 contains the deflectors 24 which deect the air from the grille I5 towards the side of the car for preventing a downblast. The jetsdischarged from the slits I2induce the flow of air from the clerc-story space 2,3v into the passage between the partitions I8,

the heated outdoor air acting* to increase the sensible heat ofthe dehumidied air. Although in this embodiment there are no recirculated air grilles for theproduction of overhead transverse air currents, the outdoor air may be expected to have a higher temperature than the'` recircukasiazzsz lated air used in Figs. 1 and 2 so that the air discharged into the passenger space will have a higher temperature so that no objectionable drafts would be produced.

The embodiment of Fig. 4 is similar to that of Figs. 1 and 2 except that it is better adapted for the modern stream-lined cars which have no clerc-story space and in which the ceiling is closer to the roof. In thisembodiment the duct II is illustrated as covered with the insulation 25 for reducing heat exchange losses. The ducts I I of Figs. 1 and 3 may of course also beso insul'ated.` AThe'outl'etgrilles I5 are placed below the oeil-ing I4 and connected to the ceiling by the converging partitions 26 which form therebetweenaconverging air passage. The converging passage aids in the air inducing action of the jets discharged thereinto, and by locating the grillesI 5 :below the ceiling I4 more space between the grilles I5 and slits I2 is provided for the induction: and mixing effects.

Utilizing this invention a' relativelyA small'volurne' ofrair may be chilled to a' relatively/low dew point temperature'and'mixed with av relatively large volume of Warmer airrlat'local dischargepoints, the low dew'pointA temperature providing;v for low relative humiditiesfin the passenger space, and A--the mixing i of the 'warm air providing: forfthedischarg'e of the air without drafts;

While' embodiments ofthe-invention havebeen describedifor 'thepurposeof illustration, it should beund'erstoodthat'the invention is not limited to the. exact apparatus `and arrangements 'of apparatus. illustrated as` modications thereof may be: suggestedxby thos'esklled in the -artwithout Vdeparture from'rthe essence ofthe invention.

Whatfis claimed.' is:

1'..An air tempering `system for a passenger vehicle having aceiling, comprising "a duct for connection to a source of `'refrigerated air under pressurelsaid duct being spaced above said ceiling. for lforming an lair space between said duct and'ceiling, said ceiling having an air outlet under saidU duct for supplying air into the passenger space, means forming an ejector con necteclV to said lduct for discharging air from Vsaid duct; in a high velocity jet, into said outlet, means forming an air inlet into said space for supplyin'gfthereu'nto, warm air from another source of air, 'whereby the air through said ejector induces t-he flow of air through said inlet for mixture Withthe ejector air prior to discharge through said outlet.

2.. An air tempering system for a passenger vehicle having a ceiling, comprising a duct above said ceiling for connection to a source of refrigerated` air underv pressure, means forming an air outlet through said ceiling into the passenger space of said, Vehicle, means forming an ejector connecting with said duct for discharging air from said. duct in a high. velocity jet into said outlet, meansforming a recirculated air inlet in said ceiling; and means forming a passage for conveying` air from. said inlet in contact with the air discharged' from said ejector, between said ejector and said outlet whereby the How of recircula-ted air' from the passenger space through said inletA and passage is induced by the ow of air through said ejector, for mixture with the air from said ejector prior to discharge of same through said outlet into said passenger space.

3. An air tempering system for ay passenger vehicle having a ceiling; comprising a duct above said ceiling for connection to a sourcecf refrigerated air under pressure, means forming an air outlet through said ceiling into the passenger space of said vehicle, means forming an ejector connecting with said duct for discharging air from said duct in a high velocity jet into said outlet, means forming recirculated air inlets in said ceiling on opposite sides of said outlet, and means forming passages for conveying air from said inlets in contact with the air discharged from said ejector, between said ejector and said outlet whereby the flow of recirculated air from the passenger space through said inlets and passages is induced by the ow of air through said ejector, for mixture with the air from said ejector prior to discharge of same through said outlet into said passenger space.

4. An air tempering system for a passenger vehicle having a ceiling, comprising a duct extending longitudinally down along the center line of and above said ceiling for connection to a source of refrigerated air under pressure, means forming an air outlet extending along the longitudinal center line of and through said ceiling into the passenger space of said vehicle, means forming an ejector in the center of the lower wall of said duct for discharging air from said duct in a high velocity jet into said outlet, means forming recirculated air inlets in said ceiling on opposite sides of said outlet, and means forming passages for conveying air from said inlets in contact with the air discharged from said ejector, between said ejector and said outlet whereby the flow of recirculated air from the passenger space through said inlets and passages is induced by the ow of air through said ejector, for mixture with the air from said ejector prior to discharger of same through said outlet into said passenger space.

5. An air tempering system for a passenger vehicle having a ceiling, comprising a duct above said ceiling for connection to a source of refrigerated air under pressure, means forming an air outlet through said ceiling into the passenger space of said vehicle, means forming an ejector connecting with said duct for discharging air from said duct in a high velocity jet into said outlet, means forming a recirculated air inlet between said outlet and one of the longitudinal sides of said vehicle, and means forming a passage for conveying air from said inlet in contact with the air discharged from said ejector, between said ejector and said outlet whereby the flow of recirculated air from the passenger space through said inlet and passage is induced by the iiow of air through said ejector, for mixture with the air from said ejector prior to discharge of same through said outlet into said passenger space.

6. An air tempering system for a passenger vehicle having a ceiling, comprising a duct above said ceiling for `connection to a source of refrigerated air under pressure, means forming an air outlet through said ceiling into the passenger space of said vehicle, means forming an ejector connecting with said duct for discharging air from said duct in a high velocity jet into said outlet, means forming recirculated air inlets on opposite sides of said outlet, and means forming passages for conveying air from said inlets in con- 5 tact with the air discharged from said ejector, between said ejector and said outlet whereby the flow of recirculated air from the passenger space through said inlets and passages is induced by the flow of air through the ejector, for mixture with the air from said ejector prior to discharge of `same through said outlet into said -passenger space.

7. An air tempering system for a passenger vehicle having a ceiling, comprising a duct above said ceiling for connection to a source of rerigerated air under pressure, means forming an air outlet through said ceiling into the passenger space of said vehicle, means forming an ejector connecting with said duct for discharging air from said duct in a high velocity jet into said outlet, and means iorming an outdoor air passage for conveying outdoor air in contact with the air from said ejector, between said ejector and said outlet whereby the air through said ejector induces the flow of outdoor air through said passage for mixture with the ejector air prior to discharge through said outlet.

8. An air tempering system for a pasenger vehicle having a ceiling, comprising a duct for connection to a source of refrigerated air under pressure, said duct being spaced above said ceiling for forming an air space between said duct and ceiling, said ceiling having an air outlet under said duct for supplying air into the passenger space, means forming an ejector connected to said duct for discharging air from said duct in a high velocity jet into said outlet, means forming an air inlet into said space for supplying thereunto, warm air` from another source of air, whereby the air through said ejector induces the flow of air through said inlet for mixture with the ejector air prior to discharge through said outlet, said outlet including oppositely inclined deflectors for delecting air from said outlet towards the opposite longitudinal sides of said vehicle.

9. An air tempering system for a passenger vehicle having a ceiling, comprising a duct above said ceiling for connection to a source of refrigerated air under pressure, means forming an air outlet through saidr ceiling into the passenger space of said vehicle, means forming an ejector connecting with said duct for discharging air from said duct in a high velocity jet into said outlet, and means forming an outdoor air passage for conveying outdoor air in contact with the air from said ejector, between said ejector and said outlet whereby the air through said ejector induces the ow of outdoor air through said passage ior mixture with the ejector air prior to discharge through said outlet, said outlet including oppositely inclined deiiectors for deecting air from said outlet towards opposite longitudinal 65 sides of said vehicle.

ROBERT T. PALMER. 

